Televisions and other types of imaging systems are pervasive in today's society. Recent years have seen the introduction of higher definition imaging systems. Engineers continue to try to increase the resolution and brightness of imaging systems to provide better picture quality, but also face constraints associated with providing such increased resolution and brightness.
For example, to increase brightness in imaging display systems, coherent light sources such as lasers may be used in the place of incoherent light sources such as light-emitting-diodes (LEDs) and lamps. However, while coherent light sources may increase the brightness of the display system, such light sources often produce images having a noticeable granularity. This grainy pattern, also known as speckle or the scintillation effect, arises due to the highly narrowband and polarized nature of the coherent light incident on a diffuse surface. Speckle has been attributed to the fact that coherent light reflected by or through a diffusing produces a complex, random, but stationary diffraction pattern. Specifically, speckle originates when the coherent plane phase front from a laser traverses through a medium with optical path length differences that are less than or equal to the coherence length of the laser. Such path length differences can occur as a result of surface roughness, scratches, digs, and polishing imperfections in optical elements.